Wikipedia's facts - electric charge
Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. There are two types of electric charges: positive and negative. Like charges repel and unlike attract. An object (one not made of antimatter) is negatively charged if it has an excess of electrons, and is otherwise positively charged or uncharged. The SI derived unit of electric charge is the coulomb (C). In electrical engineering, it is also common to use the ampere-hour (Ah), and, in chemistry, it is common to use the elementary charge (e) as a unit. The symbol Q often denotes charge. Early knowledge of how charged substances interact is now called classical electrodynamics, and is still accurate for problems that don't require consideration of quantum effects.
The electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields. The interaction between a moving charge and an electromagnetic field is the source of the electromagnetic force, which is one of the four fundamental forces (See also: magnetic field).
Can you protect yourself from failure?
Actually, modern technological solutions in the design and construction of electrical installations, make electrical services are becoming less necessary. Excellent insulation of cables and their arrangement can make the most electrical work will be the installation of such electrical lines, not during their operation. Does this mean that in the future, avoid any electrical failures? The answer to this question is simple and of course negative, because although more and better solutions are continuously implemented many failures simply impossible to predict, even using the most modern electrical installations.
The complex electrical systems
Especially in the case of large buildings electrical systems play a huge role. At the beginning should be designed and adequately equipping workers with the necessary wiring and mounting items. The installation itself mains also require supervision by a competent, highly qualified staff having qualified electrician. During the installation of electrical systems at the construction site should remain authorized persons, regardless of whether they plan to put electrical installations in the home or in a big high-rise. In each place is a risk that there is a dangerous situation is the same.